Design and Development of an Agricultural Material and Fruit Peel Shredder Machine

Abstract

This research aimed to design, develop a small cutting machine for cutting vegetables residues from households and herb plants. The procedures were as follows; study basic physical properties of materials, design, construct and test the performance of the cutting machine. The cutting machine weighs 45 kilograms. It consists of a steel structure, a feeding hopper, cutting blade set (23 curved blades 160 mm long, 2.0 mm thick), fly wheel, power transmission sets, material rails and1/3 hp electric motor. Seven types of plants including lemongrass head, lemongrass, pandan leaf, Thai morning glory, Beijing grass, pomelo peel and passion fruit peel were tested at cutting speed of 500, 600, 700, 800 and 900 rpm, the test results showed that the machine can cut materials at all speeds. The amounts of cutting were directly correlated with the cutting speed. The maximum amount of small size materials were at cutting speed 800-900 rpm but the machine was too much vibrated and materials bounced back out of the feeding hopper. While the cutting speed700–800 rpm could cut in small size materials71–148 kilograms per hour using electric power 0.0009–0.0033 kWh/kg. At these speeds the cutting machines worked smoothly without vibration, so the cutting speed 700 rpm is selected for operating the machine. The machine can cut 6 types of test plants except pomelo peel. The average cutting capacity was112.3 kg/h with average electricity consumption 0.0013 kWh/kg. For economic analysis, the machine cost was23,000 baht, it was found that the cost per cutting unit (baht/kg) at small cutting amount was high but when the amount of plants increased, the cost per cutting unit was decreased. When the cutting amount increased to 60,000–100,000 kg/year (150.5–212.0 days), the cutting costs were between 0.73–0.75 baht/kg.